This disclosure relates to evaluating cement behind a casing of a wellbore. Specifically, the embodiments described herein relate to enhancing cement evaluation by actively controlling/attenuating drill collar arrival vibrations during the cement evaluation.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions.
A wellbore drilled into a geological formation may be targeted to produce oil and/or gas from certain zones of the geological formation. To prevent zones from interacting with one another via the wellbore and to prevent fluids from undesired zones entering the wellbore, the wellbore may be completed by placing a cylindrical casing into the wellbore and cementing the annulus between the casing and the wall of the wellbore. During cementing, cement may be injected into the annulus formed between the cylindrical casing and the geological formation. When the cement properly sets, fluids from one zone of the geological formation may not be able to pass through the wellbore to interact with one another. This desirable condition is referred to as “zonal isolation.” However, the cement may not set as planned and/or the quality of the cement may be less than expected. For example, the cement may unexpectedly fail to set above a certain depth due to natural fissures in the formation.
A variety of acoustic tools, such as an ultrasonic imaging tool, may be used to verify that the cement is properly installed. For example, in a cement bond logging process, these acoustic tools may use pulsed acoustic waves as they are lowered through the wellbore to obtain acoustic cement evaluation data (e.g., flexural attenuation and/or acoustic impedance measurements). The data collected by the acoustic tools may be used to determine whether or not the cement is likely to have set properly.
Unfortunately, these tools used in downhole cement bond logging activities often operate within extreme environments, such as high temperature, high pressure, and/or high shock environments. Because these tools are oftentimes delicate and highly sensitive to external vibration, the cement bond logging process has traditionally not been feasible in a logging-while-drilling (LWD) environment, where the cement bond logging tools are incorporated to the wellbore drill string. Instead, cement bond logging has been traditionally executed as an isolated process independent from a drilling process, as the drilling process may resulting in tool-damaging debris and external vibration data (e.g., drill collar vibration) that may alter the cement bond logging results.
For example, in a traditional scenario, a drill string may be placed in the wellbore, where a drill bit may be activated to drill to a certain depth (e.g., a few 1000's of feet). Once the drilling is complete, the drill string is then removed and the cement bond logging tools are independently dropped via a wireline service. Unfortunately, this independent process is oftentimes extremely time and/or cost prohibitive because of the expense and timing of transporting, installing and uninstalling an independent wireline service to an offshore drilling rig.